Apparatus for preparing molded deep forms or diaphragms



F. RAFFLES June 23, 1936.

APPARATUS FOR PREPARING MOLDED DEEP FORMS OR DIAPHRAGMS Filed April 1, 1952 Patented June 23, 1936 APPARATUS FOR PREPARING MOLDED DEEP FORMS OB DIAPHRAGMS Frank Rallies, Chicago, Ill. Application April 1,1932, Serial No. 602,574

2 Claim.

This invention relates to the manufacture of improved molded deep forms composed of paper pulp or the like, and which products will distinguish from similar products heretofore made of 5 sheet paper.

An important object of-this invention is the provision of a novel process and apparatus for the manufacture of deep forms of material such as paper which will be molded as distinguished 10 from pressed, and which can be used in the manufacture of lamp shades, toys, containers, ornaments, diaphragms, and similar objects.

One of the important objects of thisinvention is to provide a diaphragm for use in sound re- 15 production which shall be molded in one piece and which, while being of paper, shall not be distorted in any way, and therefore, not subject to the internal stresses and strains, which distortion causes faulty reproduction in the ordi- 20 nary diaphragms.

Another of the main objects of this invention is to provide an improved process and apparatus for manufacturing diaphragms of this sort which shall constitute a simple yet efficient means for 25 producing these objects in commercial quantities While at the same time assuring a very satisfactory product.

Another and further important object of the invention resides in the provision of a seamless diaphragm for use in sound reproduction which will include a voice coil collar and a flexible suspension ring, all in one integral unit and forming a part of the cone section.

Still another and further important object of.

35 the invention resides in the production of radio diaphragms or the like wherein it is possible to control the characteristics and tone results of a paper diaphragm of this sort by changing the nature of the pulp, the distribution of the pulp in certain areas, and the compression of the fibers.

Other and further important objects of the invention will be apparent from the disclosures 45 in the accompanying drawing and following specification.

The invention, in a preferred form, is illustrated in the drawing and hereinafter more fully described.

6 In the drawing:

Figure 1 is a vertical view, partly in section, showing somewhat diagrammatically the process of manufacture of the improved pulp diaphragm of this invention. 55 Figure 2 is an enlarged detail view of one of been completed.

As shown in the drawing:

The reference numeral l0 indicates generally a tank or the like which is approximately filled with a mash of paper l2 mixed with many times its volume of water. The relative volume of the 10 pulp and water is such that the pulpy mass disintegrates and floats in the water. An agitating means is provided in the tank'so that the pulp is uniformly distributed and suspendedin water. This agitating means preferably comprises a series of paddles or the like I4 mounted on a shaft l6 driven by means-of a pulley wheel It or some other suitable contrivance.

Besides paper pulp, other materials may be used for the mash such as cotton, wool, fur, asbestos, and woodpulp, or any other substance which can be reduced to a desired stage for the resultant product. This pulp is preliminarily beaten, as in a paper mill, and in this beating stage certain sizes may be added if desired, which will aid in binding together of the fibers. Suitable dyes may also be added, or many other chemicals or ingredients to produce any desired properties in the finished material.

In the preferred embodiment of the invention; a metallic plate 20 is vertically suspended above the tank ill by means of a suitable support 22 to which it is attached by a hinged or universal connection 24. Suitable mechanism is provided so that the plate 20 is lowered into the tank and then withdrawn at regulated intervals.

The plate has an opening or a series of openings therein as illustrated at 26, and behind each opening there is connected to the plate by means of a positive seal or the like 28 a flexible hose 30, the other end of which is connected with the suction end of a pump 32. Therefore, when the plate is lowered into the water in the tank, the pump can withdraw waterthrough the opening or openings 26.

From the, pump 32 there runs a pipe 34 which empties into a remote portion of the tank l0 wherebythe drawn-oil water is returned to the in order to maintain the volume of water as desired and to avoidunnecessary waste.

Each opening in the plate 26 iscovered with a mold, each of these molds conforming to the shape desired in the resulting diaphragm. The

= mold proper is best shown at 36 in Figure 2 and is composed of metal or some other suitable material and provided with a number of perforations 38 therein of suitable size whereby a free flow of water therethrough can be maintained when the pump is acting through the hose and the plate 20 immersed in the pulp solution l2. Each mold 36 is covered with a metal or other screen 40 having very small perforations therein or of very fine mesh, and fitted to hold itself. Both the mold and the screen are mounted in position over an opening 26 in the plate 20 by means of bolts, clamps, or the like as illustrated at 42. These bolts or clamps are tightened so as to assure a positive seal. The metal screen 40 may be replaced by a screen of fine muslin or thin felt shaped in a die and placed over the main mold member 36. These screens act as filters between the pulp mash and the water.

A hinged or universal connection 24 between the plate 20 and its support 22 is provided so that the plate and its attached molds may enter the solution l2 in either an upright, horizontal or angular position, and if necessary, the .relationship of the plate to the support can be reversed. In this manner, forms or diaphragms of varying thicknesses, weight or strength can be produced depending upon the angular position of the plate or its relationship to the solution in the tank and also the time element such as the length of immersion in the tank while pumping proceeds. The depth of immersion of the plate will also control the thickness of the resultant deposit depending upon the concentration of the particular pulp or other material being used.

Mechanical control of the distance of travel of the plate below the water level and the time of immersion can be conveniently made and regulated whereby any desired thickness of the deposit formed results. The amount of deposit can also be controlled in various other ways such as by concentration of the pulp in the tank and the amount of suction.

In the drawing there is shown only one plate operating in the tank with a rim of molds thereon, but it will be obvious that a plurality of plates can operate simultaneously in the same tank and conveniently and economically turn out a great number of forms or diaphragms with a single mechanical arrangement such as this. Further, each plate with its accompanying dies can be so regulated as to depth and time of immersion that forms and diaphragms of varying and various thicknesses can be practically automatically and positively produced. Therefore, with the same tank and apparatus and with the same concentration of pulp, but with the use of molds of various sizes and various kinds and depths-of immersion, forms of various sizes and weights can be practically automatically produced.

The mechanism for moving the plates can be so arranged that suitable intervals of rest are provided either above or below the water level and independent of the action of the pumping system. Periods of rest below the water level will result in a greater deposit on the mold if such increased weight is desirable, while periods of rest above the water level can be utilized for drying the wet molded pulp on the form.

After the wet pulp has been deposited on the mold, the plate-can be again either stopped or retardedin its motion above the water level so that the operator can strip or remove the wet molded form from the mold, and the plate is then ready for another cycle or operation below the water level for the depositing of another form.

The operation can be made continuous, each attendant simply stripping of! the molds as they are completed on the plate and after the plate has been withdrawn from the water and stopped for the stripping operation. The motion of the plate can also be made continuous yet suificiently retarded so that the operator may strip the wet form from the mold while the plate is in motion, thereby enabling a continuous cycle of movement.

The wet form can be stripped from the mold in various ways, as for example, the suction action of the pump can be cut oif by means of a manually operated valve or the like 44, or this valve can be intermittently opened and closed automatically. In this manner, the form will be quite wet when stripped which is desirable for certain products. On the other hand, the bolts 42 can be replaced by quickly releasable clamps, and the entire mold lifted from the plate 20 and another mold inserted thereon after which the form can be left to dry on the original mold. Again, the molded form can be stripped by the operator without cutting off the suction, which is preferred for continuous and most economical production. This stripping can be effected by simply lifting one edge of the mold in a careful manner so as to protect the suction seal, after which the form can be readily stripped off. This plan permits the greatest capacity use of the same mold.

A still further method of removing the form is to lift the same from the original mold by means of a counterpart mold such as those shown at 46 and 48 in Figure 1, these being just the reverse of the original molds and mounted on a. fixed plate 50 to the back of which is attached a set of suction pipes or the like 52 which suction can be made greater than the suction in the hose 30, thereby transferring the form from one mold to the other, after which the same can be dried on the counterpart mold by continued suction or removed from some method of quick drying. The original molds are then ready for further production.

In order to insure uniformity on a production basis, the concentration of the filling material in the tank I!) must be maintained at a substantially exact ratio at all times, and inasmuch as the action of the mold or molds on the plate 20 and the resultant suction can be accurately controlled, the amount of pulp removed from the tank in each cycle of operation of the plate can be accurately calculated, and suitable means can accordingly be provided to replace a corresponding amount of pulp during or after each such cycle of operation of the plate 20 or a multiple of plates or molds. This can be done manually by simply adding an equal weight of pulp to the tank at regular intervals from standard containers. or a suitable feed pipe can be provided as shown at 54 leading from a source of pulp supply and controlled by a valve or the like 56 whereby the amount of pulp entering the tank is maintained constant. The agitator I6 and a baflie plate 58 having an opening 60 therein are provided in the tank to insure a thorough mixing of the materials before the newly added pulp has access to the molds, and an overflow opening 62 is provided to maintain water level, concentration, and for safety purposes.

The valve I can also be automatically controlled by means of a float in the tank or by an arm and lever arrangement attached to mpports 22 which lower and raise the plate in the tank.

- The overflow opening 62 is preferably covered with a screen so that pulp will not be wasted.

The stripped wet molded forms can be dried in any one of a number of ways as desirable, as, for example, they can be dried on forms which support them in desired shape, placed in a drying room either on the original molds or forms, or transferred to another similar form. Again, the wet forms onv a screen foundation may be placed in a housing through which heated air is drawn in such a manner-that the hot air is actually passed through the wet form through suction of an operating pump. A heated female die may be lowered onto the wet form for quicker drying. Further, the stripped form may be transferred to a male die in a press and a female die brought down over it. Both dies may be heated if desired, and in this event, suitable vents are provided for the escape of resultant steam. This last-named method is particularly desirable where precision of dimensions is required as in the manufacture of radio diaphragms. Another advantage in this method is positive control or pressure adjustment on the pulp fibers by reason of the adjustable clearance between the dies. By this method, one section of diaphragm may be made quite stiff, and another allowed to remain fairly soft. A

further advantage of this method is apparent in the size and number of the openings 38 in the 'mold 36.

Valves may also be placed in the mold operating on a certain area in such a manner that the same is closed when the mold is below the water level in the process of depositing the pulp on the screen, thereby allowing a controlled deposit of pulp at a particular area.

Sometimes when a desired area is quite thin, it will be diificult to strip the mold properly, and suitable valves can in that event be arranged which automatically open after the mold leaves the water level whereby greater suction is applied which .will dry this thin layer to such an extent that stripping can be readily effected.

It will be evident that herein is provided a process for producing sound reproducing diaphragms and similar forms or shapes for other and related products, which is economical and convenient, and which will be found to be quite eflicient. A product of desired thickness, pliability, and other properties can be practically automatically formed as desired with a minimum expenditure of time and labor. Further, the process and apparatus used is relatively simple while at the same time being economical and affording a maximum protection with a minimum of waste.

I am aware that many changes may be made and numerous details of construction varied throughout a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than as necessitated by the prior art.

I claim as my invention:

1. In an apparatus for preparing molded forms composed of accreted pulp, a tank adapted to contain a mash of a pulpy mass, an agitator in the tank, and means for insuring a' uniform concentration of the pulpy mash, said means comprising a feed pipe leading from a source of pulp supply, a valve for controlling the supply, a baffle plate between the opening from the feed pipe and the main body of the tank, said baille plate extending from the bottom of the tank to a-height somewhat below the maintained level of the mash,

edge, and a screened overflow opening in the tank to maintain a desired level above the upper edge ofthe baflle plate.

2. In an apparatus for preparing molded forms composed ofaccreted pulp, a tank adapted to contain a mash of a pulpy mass, an agitator in the tank, and means for insuring a uniform concentration of the pulpy mash, said means comprising a feed pipe leading from a source of pulp supply, a valve for controlling the supply, a baiile plate between the opening from the feed pipe and the main body of the tank, said baflle plate extending from the bottom of the tank to a height somewhat below the maintained level of the mash, said baflle being perforated adjacent its lower edge, and a screened overflow opening in the tank to maintain a desired level above the upper edge of the baflle plate, together with a plurality of molds, means for intermittently dipping the molds into the tank, suction lines leading to the rear faces of the molds for accreting pulp from the mash into the faces of the molds, and means igrn returning water from the suction lines to the FRANK RAFFIES.

. said baflle being perforated adjacent its lower 

